For one day in eight cities, you could hail a nearby ice cream truck to your location. An Uber-rented truck would roll up and hand you a cold treat before heading to the next caller's destination.

It cost Uber about $2,000 per truck in New York and the marketing ploy came together in about three weeks. It was well worth the effort. Uber picked a scorching 95 degree day and New Yorkers came out in hordes to eat up the startup.

"When you think about the cost of media, we prefer to advertise by meeting people and talking to people about the service," says Uber's General Manager of New York, Josh Moher. "We'd rather be out all day than putting up ads. The price, we think, is well worth it."

We rode around with Uber and learned more about the brilliant stunt. Watch: